Del Rio, the county seat of Val Verde County, is on U.S. Highway 90 and the Southern Pacific Railroad near the confluence of the Rio Grande and San Felipe Creek, 154 miles west of San Antonio in the southern part of the county. The Spanish established a small presidial complex near the site of present Ciudad Acuña, the Mexican sister city of Del Rio, and some Spaniards settled on what became the United States side of the Rio Grande. The developments that led to the growth of Del Rio, however, took place after the Civil War. In the arid vastness of Southwest Texas, water was the key to survival; in the vicinity of Del Rio the San Felipe Springs provided millions of gallons. A number of developers acquired several thousand acres adjacent to San Felipe Creek and developed plans to sell small tracts of rich farmland to prospective buyers. These investors formed the San Felipe Agricultural, Manufacturing, and Irrigation Company in 1868. The organization soon constructed a network of irrigation canals, completed in 1871. Soon they began to sell small tracts of land to newly arriving settlers, who then established truck farms. Residents in the area referred to the slowly developing townsite as San Felipe del Rio. Local lore says that the name came from early Spanish explorers who offered a Mass at the site on St. Philip's Day, 1635. In 1883, after the first post office was opened, the United States Postal Department requested that the name be shortened to Del Rio to avoid confusion with San Felipe de Austin.
In 1885 Val Verde County was organized and Del Rio became the county seat. Early development was dependent on the railroad, the military, ranching and agriculture, government-related employment, and retail business. Other major economic activities were focused on tourism and ties with Mexico. From the mid-nineteenth century to the present the military has played a leading role in the fortunes of Del Rio. As soon as the Mexican War was over, military expeditions into the area began with patrols and the establishment of frontier military camps at Del Rio and Camp Hudson, to the west on the Devils River. Most military activities were controlled from Fort Clark, thirty miles east, near the site of present Brackettville. In the twentieth century the government continued to use the isolated Del Rio area for different types of military training. As World War II started, the army opened a base near Del Rio, Laughlin Field, for pilot training. Later the name was changed to Laughlin Air Force Base. Ranching and agriculture have always been an integral part of the economic scene of Del Rio. During the late nineteenth century sheep and goat raisers found the scrub terrain to be an ideal place for their livestock. For many years Del Rio served as a focal point for the wool and mohair industry. The development of the railroad in the 1880s served as an impetus to development of sheep and goat ranching. During that decade the Southern Pacific, which built a line from west to east, and the Galveston, Harrisburg and San Antonio, building west, linked up forty miles west of Del Rio. In 1990 the railroad still operated and served as a major employer in Del Rio. The town was incorporated on November 15, 1911.
The binational and bicultural population of Del Rio grew from fifty in 1880 to 2,000 by 1890. Thereafter, changes were slow until the 1970s, when the population grew by 40.8 percent. In 1990 Del Rio had a population of 30,705, and in 2000 it had a population of 33,867. Early Del Rio residences and businesses were close to San Felipe Creek. After the railroad developed, housing patterns began to move north of the rail line. By the 1960s the development of retail trade along U.S. Highway 90 brought growth north of the original townsite. In addition, Amistad Dam and Reservoir, built on the Rio Grande during the 1960s, also attracted housing.
Del Rio supports a council for the arts. The town's first school was established in 1874; in 1990 schools were administered by the San Felipe-Del Rio Consolidated Independent School District. Southwest Texas Junior College and Sul Ross State University have branch campuses in the community. The area also is host to a sizable winter Texan population. Del Rio has the council-manager form of city government. The United States Customs, the Border Patrol, and the National Park Service have had a significant impact on the region.